Tic Tac Toe rules: how to play, explained simply
Tic Tac Toe takes about a minute to learn. Here are the complete rules, the eight ways to win, and answers to the questions that come up at the table.
What you need
Two players and a 3 × 3 grid of nine squares. On paper, you draw two vertical and two horizontal lines. One player uses X and the other uses O. In Britain and many Commonwealth countries the game is called Noughts and Crosses, but the rules are the same.
The rules
- Players take turns. On your turn, put one of your marks in any empty square.
- Marks stay put. Once a mark is placed it can't be moved or removed.
- Three in a row wins. The first player to get three of their marks in a line (across, down or diagonally) wins straight away.
- A full board with no line is a draw. If all nine squares are filled and nobody has three in a row, the game is tied.
That's the whole game.
The eight winning lines
There are exactly eight ways to make three in a row: three rows, three columns and two diagonals.
Not every square is equally useful. The centre is part of four lines, each corner is part of three, and each edge square is part of only two. That's why experienced players fight over the centre and the corners first.
Who goes first?
By tradition X goes first, but the rules don't require it. Going first is a real advantage, because the first player gets five marks on a full board and the second player only four. A fair way to play several games is to alternate who starts each round. The TicTacToe app does this automatically: X opens the first round, and after that the starting player switches every game.
How long does a game last?
At most nine moves. The earliest possible win is on the fifth move overall (the first player's third mark). The second player can win at the earliest on the sixth move. Most games between people last between seven and nine moves.
What's a "cat's game"?
In the United States, a drawn game is often called a cat's game. Nobody is completely sure where the name comes from. A popular explanation is that, like a cat chasing its own tail, nobody can win. Some players draw a large C over a drawn board, or mark a point for the "cat" on the scoreboard.
Common questions
Can you win with four in a row?
Not on a 3 × 3 board: the lines are only three squares long. Bigger boards with longer lines are a family of related games, covered in Tic Tac Toe variants.
Can both players win in the same game?
No. The game ends the moment someone completes a line, so the other player never gets the chance to complete theirs.
Can you skip a turn?
No. You must place a mark on your turn. (Interestingly, skipping would never help you anyway: an extra mark on the board can't hurt its owner.)
Is it possible to always win?
Not against an opponent who plays perfectly. With best play from both sides, Tic Tac Toe is always a draw. See why Tic Tac Toe always ends in a draw. Against real people, though, you can win often: here's how.
What about games where you move pieces?
Some three-in-a-row games give each player only three pieces, which they slide around the board once all are placed. Those are related games, such as Three Men's Morris, not standard Tic Tac Toe.
Keeping score over several games
A single game is short, so most people play a series. Popular formats are best of five (first to three wins) and simply keeping a running tally with draws counted separately. When one player is much stronger, try letting the weaker player always go first. For more ideas, see playing Tic Tac Toe with a friend.